Development and Clinical Evaluation of an Immunochromatography-Based Rapid Antigen Test (GenBody™ COVAG025) for COVID-19 Diagnosis

Abstract

Antigen tests for SARS-CoV-2 diagnosis are simpler and faster than their molecular counterparts. Clinical validation of such tests is a prerequisite before their field applications. We developed and clinically evaluated an immunochromatographic immunoassay, GenBody™ COVAG025, for the rapid detection of SARS-CoV-2 nucleocapsid (NP) antigen in two different clinical studies. Retrospectively, 130 residual nasopharyngeal swabs transferred in viral transport medium (VTM), pre-examined for COVID-19 through emergency use authorization (EUA)-approved real-time RT-PCR assay and tested with GenBody™ COVAG025, revealed a sensitivity and specificity of 90.00% (27/30; 95% CI: 73.47% to 97.89%) and 98.00% (98/100; 95% CI: 92.96% to 99.76%), respectively, fulfilling WHO guidelines. Subsequently, the prospective examination of 200 symptomatic and asymptomatic nasopharyngeal swabs, collected on site and tested with GenBody™ COVAG025 and EUA-approved real-time RT-PCR assay simultaneously, revealed a significantly higher sensitivity and specificity of 94.00% (94/100; 95% CI: 87.40% to 97.77%) and 100.00% (100/100; 95% CI: 96.38% to 100.00%), respectively. Clinical sensitivity and specificity were significantly high for samples with Ct values ≤ 30 as well as within 3 days of symptom onset, justifying its dependency on the viral load. Thus, it is assumed this can help with the accurate diagnosis and timely isolation and treatment of patients with COVID-19, contributing to better control of the global pandemic.

Development, Analytical, and Clinical Evaluation of Rapid Immunochromatographic Antigen Test for SARS-CoV-2 Variants Detection

“…In contrast, covalent conjugation used in this study requires fewer antibodies and the stability of antibody-conjugated gold nanoparticles increases. As a result, the sensitivity of our proposed method was markedly high (96.49% and 98.33%) compared to that of other commercially available diagnostic kits using the passive adsorption method (90.00%; 95% CI: 73.47% to 97.89%) [ 12 ].…”

“…Generally, the Ag-RDTs for a clinical COVID-19 diagnosis are less sensitive than the viral NAATs. The sensitivity of the commercial Ag-RDTs compared to RT-PCR ranges from 42 to 90%, and their specificity ranges from 61.2 to 100% [ 10 , 11 , 12 , 13 , 14 ]. However, repeated VOC outbreaks highlight the need for a test capable of detecting SARS-CoV-2 VOC with high sensitivity and a low limit of detection.…”

Rapid Test Ag 2019-nCoV (PROGNOSIS, BIOTECH, Larissa, Greece); Performance Evaluation in Hospital Setting with Real Time RT-PCR

“…On the other hand, when the Rapid Test Ag 2019-nCoV (ProGnosis Biotech SA) was used for antigen semi-quantification with an S-flow reader, the correlation demonstrated by linear regression analysis was weak (R 2 = 0.288). Since in the recent literature there are studies [19] supporting the potential of rapid semi-quantification of the viral load using RAT, the improvement of the test towards that direction remains a future challenge.…”

Diagnostic performance of the Elecsys SARS‐CoV‐2 antigen assay in the clinical routine of a tertiary care hospital: Preliminary results from a single‐center evaluation

“…A diverse range of rapid point‐of‐care antigen tests for the detection of SARS‐CoV‐2 from nasopharyngeal swabs and oropharyngeal swabs are currently available in the market. Some excellent publications have described the evaluation results for these rapid point‐of‐care assays, 17 , 18 , 19 , 20 , 21 , 22 , 23 and meta‐analyses on this topic have also been published. 15 , 16 A summary of the published data suggests that the sensitivity of these rapid point‐of‐care antigen assays is generally low, ranging from 20% to 95% depending on the assay and the virus load.…”